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Zcash activates NU6.2 hard fork after Orchard flaw fix as Hayes exits ZEC

Zcash activates NU6.2 hard fork after Orchard flaw fix as Hayes exits ZEC

After Zcash fixed a critical Orchard vulnerability and restored shielded transactions, Arthur Hayes said he sold all his ZEC as debate over possible counterfeit issuance and supply integrity intensified.

ZEC

Fact Check
Multiple independent sources corroborate the claim. Solid Intel's original X post explicitly states Zcash produced no blocks in the past 4 hours. Three block explorers (miningpoolstats, zcashinfo via search snippet, blockchair via search snippet) confirm the cited block height of 3,364,601. The Zcash Solo Mining dashboard shows jobs paused with a stale template at the same height. The halt aligns with a publicly announced emergency coordinated network upgrade for the Orchard pool, retweeted by the official @Zcash account on June 2, 2026, and reported by dmarketforces.com. Time math (block at 05:27:48 UTC, Solid Intel post at 09:30:52 UTC) supports 'more than 4 hours'.
Summary

Zcash completed its NU6.2 hard fork after privately coordinating an emergency response to a critical Orchard forging vulnerability that could have allowed invalid state transitions, double-spending and potentially undetectable counterfeit or extra-minted ZEC within its shielded pool. Researcher Taylor Hornby discovered the flaw on May 29, 2026 while conducting protocol security research for Shielded Labs, and the Zcash Foundation said engineers confirmed it within hours. A revised emergency soft fork activated on June 2 at block height 3,363,426 to reject Orchard transactions and blocks, and the NU6.2 hard fork activated on June 3 at block height 3,364,600 to restore Orchard with a corrected circuit. The Foundation said there was no evidence of exploitation, no unauthorized value creation, no impact to user privacy and no breach of the 21 million ZEC supply cap, while also noting Orchard’s privacy means it cannot be cryptographically proven whether the flaw had been exploited before the fix. Separately, Arthur Hayes said he sold all his ZEC because extra minting appears very unlikely but cannot be ruled out with complete cryptographic certainty.

Terms & Concepts
  • Orchard: Zcash’s newest shielded pool for private transactions and a core part of its privacy architecture.
  • forging vulnerability: A flaw that could let attackers create counterfeit tokens or trigger invalid state transitions.
  • turnstile mechanism: A Zcash safeguard that tracks value across pools and addresses to protect the total ZEC supply from unauthorized creation.